Green Production of Planar Aligned Dense 2D Nano-oxides on CNT Paper by Ultrafast Laser-Induced High-Pressure Photochemistry for Stable High-Rate LIB Anodes

Green production of functional nano-oxides on a large scale is crucial for the modern manufacturing industries. Traditional hydrothermal methods and ball milling are usually time-consuming and require long-term energy input with undesired by-products. Herein, an ultrafast laser-induced high-pressure photochemistry manufacturing technique is developed to massively produce planar-aligned graphenecoated two-dimensional (2D) SnO2 nanoplatelet on carbon nanotube (CNT) paper under the green chemistry guidelines. The unique design of Z-axis confinement added to the ultrafast laser irradiation provides an exceptional high temperature of 1772 K and a high pressure of 24 GPa in the localized laser plasma plume. This transient nonequilibrium condition controls the formation of 2D SnO2, and the ablated C atoms cool down afterward as in-situ "glue" to intactly seal the oxides on the CNT substrate. The resultant hierarchical Graphene@2D SnO2@CNT paper anode for Li-ion battery has an outstanding capacity of 819 mAh g-1 (1637 mAh cm-3) at 0.5 A g-1 and retains 622 mAh g-1 (1245 mAh cm-3) at 5.0 A g-1. The high capacity at 0.5 A g-1 has a retention of 92% after 600 cycles. This work provides an environmental-friendly scalable manufacturing technique to produce functional nanocomposites in 1 step.